Tuesday, August 10, 2010

Straightforward study that explored the impact of the great social experiment in which the past 40 years of low-fat recommendations have placed us.

The study looks at the risk of having a heart attack as a function of macronutrients in 57,053 Danes over a 12 year period and then re-analyzes risk on the basis of the glycemic indices of their carbohydrate choices.

The researchers used two models to investigate the risk of heart attack with a higher energy intake from carbohydrates and a concomitant lower energy intake from saturated fats (just like what we're still being told to do by national dietary guidelines, health organization and health related NGOs). The first model looked at macronutrients as a percentage of total energy intake. The second model further subdivided the carbohydrates into tertiles of dietary glycemic index. Both models controlled for alcohol intake, smoking status, physical activity and hypertension.

The results probably won't surprise you.

Folks who replaced saturated fats with high glycemic index carbohydrates (Wonder Bread for instance), had a statistically significant increase in their risk of heart attack, and while not statistically significant, replacing saturated fats with low glycemic index carbs appeared protective.

What's surprising to me aren't these results but rather the fact that the blind low-fat message is still being put out there by governments and health organizations who if they don't know better, certainly should.

What we should be telling folks to do is substitute healthy fats for unhealthy ones and perhaps more importantly, telling folks to substitute low glycemic index carbohydrates for high (or more simply put, whole for refined).

10 comments:

I consume a lot of fats from walnuts, pecans, ground flaxseed, wild salmon, and avocado. And I try to avoid bread. Unfortunately, even one bite of bread is enough to send me into an all-out carbohydrate binge.

I'm glad to see you mention the use of whole grains. I see a lot of sites that use these studies as an excuse to eat nothing but meat and dairy and totally ignore the evidence that whole grains, fruits, vegetables, and beans are actually quite healthy.

I'm curious as to why you still believe that whole grains are really that much better than refined. Sure, they may take a little longer to be converted to glucose but in the end they have pretty much the same effect. If you haven't read Good Calories, Bad Calories by now (and frankly I would be very surprised if you haven't, being that your profession deals with obesity) then you really need to. Wonder Bread = Whole Wheat Bread = Sugar.

While it's been a while since I read it, I seem to recall Gary in his forward explaining how in fact it's not a thorough review of all the evidence but rather a review of the evidence that would suggest saturated fats aren't all that bad.

That aside I'd also point out that regardless of whether or not you love Gary's work, my post doesn't contradict Gary's views at all, but please don't let that stop you from getting all excited.

Maybe you only read the forward then? He does indeed make the case that saturated fats are not bad by discrediting the "lipid hypothesis". He then goes on to state his case that it is the carbohydrates that are "bad". In fact, there are three chapters named "the carbohydrate hypothesis" I - III. Hence the title, "Good Calories, Bad Calories" and the picture on the cover of a piece of toast with a pat of butter. I'm not trying to pick a fight with you here but I'm just questioning your condemnation of Wonder Bread and not of bread in general. According to http://www.diabetesnet.com/diabetes_food_diet/glycemic_index.php the glycemic index of white bread is 70 and wheat bread is 68. I would call that a negligible difference.

Then there is just the general problem that glycemic index is among the most unreliable instruments out there.

For example, white potatoes may range from a low to a high GI, given on whatever list you happen to consult and, as foods usually are eaten in combinations, we are further left in the unclear. A steak (GI 0), potatoes (GI 56-111) and lettuce (GI 15) all have different numbers.

Which one are we supposed to go by?

For that matter, how did Jakobsen et al. calculate it? In the full text, the authors write:

"A GI database was compiled by using published GI values."

Methinks using a different database might have seen an entirely different outcome. This is further complicated by the fact, as many studies on nutrition, it relied on self-reporting by its subjects.

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Family doc, Assistant Prof. at the University of Ottawa, Author of The Diet Fix, and founder of Ottawa's non-surgical Bariatric Medical Institute - a multi-disciplinary, ethical, evidence-based nutrition and weight management centre. Nowadays I'm more likely to stop drugs than start them. You can also follow me on Twitter and Facebook.

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